Process of removing dyestuff from foam backing



United States Patent 3,432,251 PROCESS OF REMOVING DYESTUFF FROM FOAMBACKING Sallie A. Fisher, Berwyn, Pa., assignor of three-fourths toRobinette Research Laboratories, Inc., Berwyn, and

one-fourth to Techniservice Corporation, Lester, Pa.,

both corporations of Pennsylvania No Drawing. Filed June 23, 1965, Ser.No. 466,427 US. Cl. 8-102 11 Claims Int. Cl. D061 3/00 ABSTRACT OF THEDISCLOSURE The treatment of dyed solid foam-backed textile material,such as carpeting, particularly selective removal of dyestulf from thefoam backing thereof without significantly affecting the dyeing of thetextile component, such as carpet yarn.

When solid foam-backed textile material, such as carpeting, is dyed in abath the foam backing is likely to sorb dyestuff from the bath, andnormal rinsing procedure is ineffective to remove the sorbed dyestufffrom the backing. On some floor surfaces the retained dyestuff maytransfer from the backing to the floor surface to produce anobjectionable staining. This is a particular problem with disperse-dyed,polyurethane foam-backed, nylon carpets on vinyl tile floors.

A primary object of the present invention is prevention of theaforementioned carpet staining of vinyl floor tile or other flooringmaterial.

Another object is selective desorption of dyestuif from the backingcomponent of dyed solid foam-backed textile material without disturbanceof the dyestulf on the textile component thereof.

A further object is provision of solvents and procedures foraccomplishing the foregoing objects.

Other objects of this invention, together with means and methods forattaining the various objects, will be apparent from the followingdescription and examples.

In general, the objects of the present invention are accomplished bytreating dyed solid foam-backed textile material with an appropriatesolvent for the dyestuif and then removing the solvent in liquid formtherefrom with the dyestuff from the backing component of the textilematerial dissolved therein, without significantly affecting the dyestuifon the textile component thereof.

Suitable solvents are organic compounds containing carbonyl groups, suchas organic acids and esters thereof, aldehydes, and ketones, preferablyliquid at and somewhat above ordinary room temperature. Examples ofclosely related operable compounds from these various classes includeacetic acid, ethyl acetate, and acetone. Acetaldehyde has too low aboiling temperature to be useful, but salicylaldehyde is suitable.Another Suitable acid is 2- ethylhexoic acid. However, the ketones arepreferred, such as, in addition to acetone, the following: diacetonealcohol, methyl isoamylketone, and methyl isobutylketone.

The solvent may be applied by immersing the textile material therein orby spraying the solvent thereon, in which event the operatingtemperature may be fixed at or above (usually not below) roomtemperature. A modified form of hot application may be accomplished byvolatilizing the solvent, condensing it onto the textile material, whichis kept at room temperature or otherwise relatively cool, and drainingoff the condensed solvent with dyestuff removed from the foam backingdissolved therein.

2 Example 1 A section of nylon carpet backed with polyurethane foam anddisperse-dyed to a deep shade of blue was cut up into small squares.These squares were dipped into a variety of anhydrous organic solventsfor a suflicient length of time to wet out both the foam and the facefibers. The solvent-Wet squares of carpet were then squeezed betweenwhite paper towels, and the success of the extraction was evaluated interms of the removal of color from the foam back and the absence ofevidence of color removal from the face fibers as shown by the absenceof color on the paper squeezed in contact with the face of the testsample.

Typical results from the variety of solvents employed in Example 1 aretabulated in Table I. Solvents rated as very good in extraction arethose wherein the foam color Was changed from a deep blue to white in asingle extraction. Good solvents are those in which the removal left thefoam light or faintly blue, a fair extraction showed some lightening ofthe foam color, a poor rating is indicated by only traces of color onthe paper during the extraction process, and a very poor ratingindicated no evidence of extraction.

TABLE I Solvent: Dye removal from backing Acetic acid Very good. Acetonedo. Ethyl acetate do. Methyl isobutylketone do. Salicylaldehyde Good.Diacetone alcohol do. Methyl isoamylketone do. 2-ethylhexoic acid do.1,3 butyl glycol Fair. Diethylene glycol Poor. Ethylene glycol do. Hexylalcohol do. Isopropyl alcohol Very poor.

Example 2 Sections of polyurethane foam-backed nylon carpet which hadbeen disperse-dyed a brilliant blue, a vivid purple, and a dark red weresoaked in separate portions of acetone and diacetone alcohol at ambienttemperatures. These samples were then removed from the solution,squeezed as dry as possible by passing through pressure rollers, washedwith water and dried. In no case was there a difference in face colorbetween the extracted samples and pieces of the same carpet beforeextraction. The success of the extraction in terms of color of the foamside was good, in the case of the blue and purple rugs, with bothsolvents. Extraction of the red carpet was rated as somewhat lesssuccessful (Table II) in terms of the residual foam color. Sections ofextracted carpet were placed with their foam side against white vinyltile, along with unextracted portions of carpet. The samples wereweighted down to insure good contact between the foam and the tile andheld in a constant temperature oven at C. for three days. No transfer ofdye from the extracted foam to the tile was noted. In the same length oftime the unextracted blue carpet had stained the tile deeply, the purpleproduced a stain of moderate intensity and the red a light stain.Therefore, it is concluded that while the extraction of the red dye withthe two solvents had not greatly reduced the observed color, the dyethat migrates to the tile had been removed in the process so Example 3Sections of the same three polyurethane-backed nylon carpets used inExample 2 were hung in a device of such design that when a solvent wasboiled in it its vapors condensed on the carpet sample and the liquidformed therefrom dripped back into the still pot. Separate experimentswere conducted using, on the one hand, acetone and, on the other hand,diacetone alcohol as the solvent. Extraction of the three rug colorswith hot acetone took place very rapidly with no loss of color of theface yarn. Extraction with higher boiling diacetone alcohol was somewhatslower and in the case of the red carpet visibly complete (Table H). Theextracted samples were again squeezed to remove excess solvent and werewashed with water and dried. They were tested on white vinyl tile asdescribed in Example 2. Again no transfer of dye from the extractedsamples to the tile was noted.

Example 4 Polyurethane-backed polyester carpets that had beendisperse-dyed a medium blue, a deep red and a medium brown were testedfor extractability with acetone and diacetone alcohol at ambienttemperatures using exactly the same procedure as that described inExample 2. Again the extraction of color from the foam dyed with the reddye was less complete than that of the other two colors. The results aresummarized in Table III under the heading Cold. When these extractedcarpets were placed on a white vinyl tile, foam side down, and weighteddown and held in an oven at 70 C. for three days in comparison withunextracted carpet under the same conditions, the extracted carpetsagain did not stain the white tile. Staining from all three unextractedsamples was very dark.

TABLE III Extraction Solvent Rug color Cold Hot Acetone... BlueGood.-.-- Good.

Do.. Red Fair Do. Do Brown Good....- Do. Dlacetone alcohol Blue ..do Do.Do Red Poor Fair. Do Brown Good..... Good.

1 Slight loss of face yarn dye.

Example 5 Samples of the same three polyurethane-backed polyestercarpets used in Example 4 were extracted following the procedure inExample 3 utilizing the vapors of acetone and diacetone alcohol. Theresults are summarized in Table III under the heading Hot. As indicated,the extraction of all three colors by acetone was good. Extraction withdiacetone alcohol, however, resulted in some loss in face color beforethe color was completely removed from the foam side. This wasparticularly noticeable in the blue and the brown rugs. When thesehotextracted samples were tested on white vinyl tile as previouslydescribed no staining of the tile was noted.

I claim:

1. Process of removing water-insoluble textile dyestuff selectively fromthe solid foam backing of dyed solid polyurethane foam-backed textilematerial while leaving the textile material dyed with the dyestuff,comprising applying to the dyed material, as solvent for the dyestufi, acarbonyl-containing liquid from the class consisting of acetic acid,acetone, ethyl acetate, methyl isobutylketone, salicylaldehyde,diacetone alcohol, methyl isoamylketone, and Z-ethylhexoic acid, andsubsequently removing the solvent in liquid form therefrom with dystulffrom the foam backing dissolved therein.

2. The process of claim 1 wherein the solvent is condensed from vaporform onto the textile material and then drained therefrom.

3. The process of claim 1 wherein the textile material is immersed inthe solvent, which there after is removed therefrom by squeezing.

4. The process of claim 1 wherein the textile material has a nylontextile component.

5. The process of claim 1 wherein the textile material has a polyestertextile component.

6. Process comprising treating carpeting composed of dyed solid foambacked textile material with a liquid from the group consisting ofacetic acid, acetone, ethyl acetate, and methyl isobutylketone assolvent for the dyestuff, which is water-insoluble, dissolving thedyestuif selectively from the solid foam backing while leaving thetextile material dyed with the dyestulf, and removing therefrom theresulting solution of the treating solvent and dyestuif dissolvedtherein.

7. The process of claim 6 wherein the foam backing comprisespolyurethane.

8. The process of claim 6 wherein the textile material is nylon.

9. The process of claim 6 wherein the dyestulr' is a disperse dyestuif.

10. Process of removing water-insoluble disperse dyestuff selectivelyfrom the foam component of dyed solid polyurethane foam-backed nylontextile material useful as a floor covering while leaving the textilecomponent dyed with the dyestuif, and thereby rendering the samenon-staining to floor tile as when in place on a vinyl tile floor,comprising treating the textile material with diacetone alochol todissolve the dyestuff from the foam component and removing the solventin liquid form therefrom with dyestuff dissolved therein.

11. Process of removing water-insoluble disperse dyestulf selectivelyfrom the foam component of dyed solid polyurethane foam-backed polyestertextile material useful as a floor covering while leaving the textilecomponent thereof dyed with the dyestuff, and thereby rendering the samenon-staining to floor tile as when in place on a vinyl tile floor,comprising treating the textile material with acetone to dissolve thedyestulf from the foam component and removing the solvent in liquid formtherefrom with dyestulf dissolved therein.

References Cited UNITED STATES PATENTS 2/ 1925 Kocher 8-102 10/ 1950Koberlein 8-102 OTHER REFERENCES MAYOR WEINBLATT, Primary Examiner.

US. Cl. X.R.

